"This was in harmony with the gospel plan of uniting in one body all believers in Christ, and this plan Paul was careful to follow throughout his ministry. Those who in any place were by his labor led to accept Christ as the Saviour were at the proper time organized into a church. Even when the believers were but few in number, this was done. The Christians were thus taught to help one another, remembering the promise, “Where two or three are gathered together in My name, there am I in the midst of them.” Matthew 18:20 . AA 185.3"
"For where two or three are gathered together in my name, there am I in the midst of them."
Ellen White directly references Matthew 18:20 in this passage.